Electrical gas discharge tube circuits



Jan. 13, 1959 J. H. BEESLEY 2,869,035

ELECTRICAL GAS DISCHARGE TUBE CIRCUITS Filed Feb. 4, 1955 2 Sheets-Sheetl Von/1a: SIG/VAL Sou/m5 J20 HWORNEY Jan. 13, 1959 J. H. BEESLEY2,869,035

ELECTRICAL GAS DISCHARGE TUBE CIRCUITS Filed Feb. 4, 1955 2 Sheets-Sheet2 cathode forming a main discharge tubes connectedin a chain,

- reference to the two figures of the accompanying thence by way UnitedStates Patent 2,869,035 ELECTRICAL GAS DISCHARGE TUBE: cmcurrs JohnHenry Beesley, Coventry, England, assignor to The General ElectricCompany Limited, London, England Application February 4, 1955, SerialNo. 486,237

Claims priority, application Great Britain February 5, 1954 19 Claims.(Cl. SIS-84.5)

This invention relates to electrical circuits. electrical counting ordistributing circuits that employ gas discharge tubes of the kind havingan anode and a gap and a striker electrode forming an auxiliary,discharge gap with the cathode, such gas discharge tubes beinghereinafter referred to as gas tubes.

-An object of the present invention is the provision of an improved formof electrical gas tube counting or distributing current.

According to the present invention, a gas tube counting or distributingcircuit, comprises a plurality of gas at least two input leads to whichthe signals to be counted or distributed are applied, and connectionsbetween adjacent gas tubes of the chain and between the said gas tubesand the said input leads so that, when one of the said gas tubes is gasdischarge tube conducting a striking potential is applied to the strikerelectrode of the following gas tube in the chain when at-least apredetermined voltage is applied to a particular one of the said inputleads.

The striking gap discharge current of the said conducting tube.

Preferably, each of the said gas tubes is a cold cathode gas dischargetriode.

The operation of a gas tube counting or distributing circuit accordingto the present invention may be substantially independent of the shapeof an input signal pulse. Two or more such counting or distributingcircuits may therefore be connected in cascade by means of individualelectrical connections from the input leads of one such circuit each toa difierent output of a similar preceding circuit, there being no pulseshaping between the two circuits.

One arrangement in accordance with the present invention will. now bedescribed, by way of example, with diagrammatic drawings, which arecomplementary illustrations of the electrical circuit of a countingcircuit.

The circuit comprises an even plurality N of gas tube counting stages ofwhich the first three tubes 1, 2 and 3 are shown in Figure 1 and thelast two tubes (N-l) and N are shown in Figure 2. The counting stagesare arranged in a closed chain. Each of the gas tubes is a cold cathodegas discharge triode, and has an anode4, a striker electrode 5 and acathode 6. The anodes 4 are connected to a common lead 7 and of aresistor 8 to a terminal 9.

The electrical circuit of each counting stage is identical.- Thus thegas triode 2 'say has its cathode 6 connected to earth by way of aresistance-capacitance net work comprising in one of two arms that areconnectedin parallel a resistor 34 and in the other arm a resistor 35and a capacitor 27 in series. This cathode -6 is also connected to thestriker electrode 5 of the succeeding'gas triode 3 of the chain by wayof a re- The invention is particularly concerned with potential may bederived from the main sistor 10 and a rectifier element 11. Therectifier element 11, hereinafter referred to as a striker rectifier, isconnected so as to afford a low resistance to conven tional current flowtowards the striker electrode 5 of the triode 3, it function being asdescribed in the specification of co-pending British patent applicationNo. 36,375/53.

Two input leads 12 and 13 are provided, the voltage signals to becounted being applied to these leads by way of terminals 14 and 15respectively. Each of the leads 12 and His connected to earth by way ofa resistor 16 or 17. Such potentials asare developed across theresistors 16 and 17 duringoperation are isolated from the terminals 14and 15 by means of the suitably connected rectifier elements 18 and 19respectively.

The junction of the resistor 10 and the striker rectifier 11 isconnected to the input lead 13 by way of a rectifier element 22,hereinafter referred to as a junction rectifier, so connected as toafford a low resistance to conventional current flow towards the lead13. The junction rectifiers 20 to 25 are associated each with adifferent one of the gas triodes and are connected to the leads 12 and13 in a cyclic order, that is, alternate junction rectifiers along thecounting chain are connected to the same lead 12 or 13.

During operation, the terminal 9 is connected to a source of positivepotential of insuflicient: magnitude to initiate a main gap discharge ina gas triode but sufiicient to maintain such a discharge once initiated.The positive voltage signals to be counted are applied alternately tothe terminals 14 and 15.

Let it be assumed that the gas triode 1. is conducting across its maingap. Its cathode 6 is then at a positive voltage with respect to earthby virtue of the discharge current flowing through the resistor 26. Thevalue of this voltage is sufiicient to initiate a striker electrode tocathode discharge in the gas triode 2 when applied across theseelectrodes. In the absence of a suitable positive voltage signal on thelead 12 the junction rectifier 21 is conductive. The striker electrode 5of the gas triode 2 is thus maintained below the voltage necessary tocause striking. Application of a suitable positive voltage signal to theterminal 14, and hence to the lead 12, biasses the junction rectifier 21to a non-conductive condition. The voltage at the striker electrode 5 ofthe gas triode 2 therefore rises and an auxiliary gas discharge isinitiated in this tube. The gas triode 2 consequently strikes bytransfer of the said discharge to its main discharge gap, Such transferbeing effected by virtue of the positive voltage on the anode 4 of thisgas triode 2. The resulting discharge current flows through theresist-or 8 and the voltage on the lead 7 thus falls below the dischargemaintaining value for the main gap of the gas triode 1. This dischargein this gas triode 1 is therefore extinguished. The main gap dischargecurrent of the gas triode 2 charges the capacitor 27, the cathodevoltage of this gas triode rising from earth to a value sufficient toinitiate the striking of the gas triode 3 although that triode does notstrike owing to its striker electrode voltage being held down due to thefact that the junction rectifier 22 is conducting.

The next voltage signal is applied to the terminal 15 and acts to biasthe junction rectifier 22 to a non-conductive condition. The gas triode3 therefore strikes, the gas triode 2 being extinguished in the mannerpreviously described. In this way each positive voltage signal appliedalternately to the terminals 14 and 15 is registered by the striking ofone of the gas triodes, the gas triode is signified'by the presence of apositive voltage with repeac es 3 spect to earth on the appropriate oneof the output terminals, such as the terminals 28. to.32.

The striking of the gas triode N, resulting from both the application ofa voltage signal to the terminal 14 and the occurrence of a suitablepositive voltage at the cathode 6 of the gas triode (Nr-l), causes thevoltageof the lead 33 to become sufliciently positive to initiate. the.striking of the gas triode 1 when the next voltagev signal is applied tothe terminal 15. The counting circuit thus continues to function for aslong as suitable voltagesignals are applied alternately to the terminals14 and 15.

When only twoinput leads, such as the leads 12 and 13, areprovided, a,false, count may result if the input signals overlapin time, that is, itsuitable. positive voltages exist simultaneously on, both leads. Thiscondition may be overcome by providingthree or more input leads,

the junction rectifiersbeing connected cyclically to these leads.

When the counting stages, are. connected in a. closed chain, as in thearrangement. illustrated and described above, it is essentialthat, thenumber ofcounting stages is amultipleof thenumber of input leads if allthe input signals aref'to be counted or'distributed correctly. Thus.with the counting circuit illustrated, hadthere been an odd number ofstages, then both junction rectifiers and would have been connectedtothe sameinput lead Inthis case the application of avoltage signal tothe lead 1;; to. initiate the striking of thegastriode N could alsoresult in the striking of the gas triode 1 if, thesaid voltage. signalisrnaintainedfior a sufiicient; period. Alternatively, if only-thegastriode N is struck as a result of thesaidvoltage signal, the ne ttvoltage signal, which is applied to the lead 12, will be. of no effect.In either alternativeafalse count- -results Although the invention hasbeendescribed -inits application to closed; chaincir-cuits it is notnecessarilyrestricted to sucharrangements, Thus, when the number ofsignals; to be countedon distributed at anytime; lies withinpredetermined limitsit is usually required: that;- a count shall always:commence-from a predetermined one of. the gas tubes, as forexamplethegas triode 1. In this event the lead 33, can be omitted, as also can thejunction rectifier 20, Arrangements are made whereby when the circuit istaken into use the gas triode 1 is struck previous to the application ofvoltage signals to the leads 12 and-13. This may be efiected by applyinga suitable positive voltagetothe striker rectifier 36. The firstvoltagesignal is then applied to the input lead 12, and is registered bythe striking of the gas triode 2, the gas triode [being extinguishedinthe manner previously described] Itwill beappreciated from the abovedescription that the junction recti ti ers, such as. the rectifiers; 20to 25, are substantiallynon-conductive totheivoltage signals on theinput leads, so that the input current flowwhich results from such Yavoltage signal issubstantiallyindependent of the number of counting ordistributing stages.

The use of the term junction rectifier tor the rectifier elements 20 to25 should ,be interpretcd asr elating to the loca o oft-these 1. ms...hes ls tifls i lsm t0- a h rth.- hcf t re att s smsats t 19 d nm tes..,.d.; b..y ,te P ctctah y,. .fia. yp t It is sometimesrequiredtoconnect two; or n orc counting or distributing circuits incascade and in knownarrangements it is usually. necessary to employpulse shaping devices in the inter-.connections, Such anecessity. doesnot arise with circuits of the present form sincetheir operationdependsupon potential levelsandrnay be substantially independent of theshape of the input signals. Individual connections may thus be made fromthe input leads of one such gas tubecircuit each to a different outputof a preceding circuit, there being no pulse shaping between the two. Ifnecessary more than one outputmays n s ed a he me item. at trectifi r.lstasat are included in the said connections, the said rectifierelements being so. connected as to isolate from one another the saidoutputs without inhibiting the application of signals to the associatedinputlead.

The voltage signals that are supplied to the input leads l2 and 13 maybe derived from any suitable source 37, an example of such a sourcebeing a bi-stable trigger circuit,

I lsim:

Ant cs r Circuit co p s n a l ra of a d charge tubes which each has ananode, a cathode and a strikerelcctrode, a small. pluralityofinputleads,rneans to apply ta n s. ashc a redetermi e value. to the inputleads a particular sequence so that such a voltage signal occurs on onlyone input lead at a time, and a plurality; of: gating circuits which.connect the gas tubes in a chain for sequential striking in response tovoltage signals of the predetermined value occurring in the particularsequence on the input leads, each gating circuit coupling a differentpair of adjacent gas tubes in a chain and having a first input connectedto the first gas tube of its associated pair, a second input connectedtoone of the input leads and an output connected to the strikerelectrode of the second gas tube of its associated pair, adjacent gatingcircuits in the chain having their second input connected to differentones of the saidinputleads and each gating circuit enabling the secondgas tube of its associated pair to be rendered conducting in response toa voltage signal of the predetermined value on the associated input leadonly if the first gastube of the pair is conducting.

2. An electric-circuit according to claim 1 inwhich the saidgatingcircuits connect said gas tubes in a continuous chain.

3. An electric. circuit according to claim- 1 inwhich individualresistance means is connected to the; cathode ofeach. gas tube to derivea-voltagesignal ofjthepredetermined-value from thedischargecurrentthrough the gas tube, when conducting, and inwhich-said; gati gg rcuit has its first input connectedto-thecathodeofithefirst-gas tube of the associated pair.

4. An electric circuit according to claim 3 in which individualcapacitance means is provided for each gas tube, each said capacitancemeans being connected in shunt with the individual resistance means ofthe. associatedgas tube to provide an exponential rise and fall to thevoltages developed across said individual resistance meansin which thereare provided resistance connected in commonto the anodes of the gastubes and mutual extinguishing means including the common resistance andthe individual capacitance means whereby theconduction ofany one ofsaidgas tubes causes any previouslyconductinggas tube. to be extinguished.

5 An electric circuit according toclaim 1 in which said gas tubes arecold cathode gas discharge. triodes 6 An electric circuitcomprisingapluralityof'gas discharge tubes which each has an anode, a.cathode anda striker electrode, a small plurality-of input leads, meansto apply voltage signals, each of a predeterminedvalue, to the inputleads in a. particularsequenceso; that such voltage signal occurs; ononlu-oneinputlead; atatim tanceconnected in common to. the anodesof thegas tubes, a; plurality ocapacitance means; each connected to thecathodev of, a diiferent one. of the. gas tubes, mutual extinguishingmeans including said; resistancev and said capacitance means whereby theconduction, ofsany oneof the gas tubes; causes any previously conductinggasv tube to be extinguished and aplurality of gating circuitswhichconnect-the gas tubes in a chainfonsequential striking, oneat a time,inresponse to voltage signals, oi the; predeterminedvalue occurring inthe pur-ticulap sequc cfirq the input leads, eachgatingcircuit-couplingadifiercnt pair of adjacent gas tubes; inthe,chain;and haying; a.first input connected to the cathode of thefirsft gas, tube of haa ss iaz e as nass s td npu csnna tcd an ent h inputleads and an output connected to the striker electrode ofthe second gastube of the associated pair, adjacent gating circuits in the chainhaving their second inputs connected to different ones of the said inputleads and each gating circuit enabling the second gas tube of itsassociated pair to be rendered conducting upon the occurrence of avoltage signal of the predetermined value on the associated input leadonly if the first gas tube of the pair is conducting.

7. An electric circuit according to claim 6 in which the said gatingcircuits connect said gas tubes in a continuous chain.

' 8. An electriccircuit according to claim 6 in which said gas tubes arecold cathode gas discharge triodes.

9. An electric circuit comprising a plurality of gas discharge tubeswhich are each of the kind having an anode, a cathode and a strikerelectrode and which are connected in cascade to form a chain, individualresistance means connected to the cathode of each gas discharge tube toderive a voltage signal of predetermined value from the dischargecurrent through the gas tube when conducting, a small plurality of inputleads, means to apply voltage signals, each of at least the saidpredetermined value, to the input leads in a particular sequence so thatsuch a voltage signal occurs on only one input lead at a time, aplurality of signal coincidence circuits which each has a first input, asecond input and an output and which are each arranged to act upon thecoincidence of voltage signals of the said predetermined value on thefirst and second inputs to gate a voltage signal of the same value tothe associated output, connections between the first inputs of the saidcoincidence circuits and the said resistance means to apply to the firstinputs the said voltage signals derived, during operation, at the saidresistance means,

, connections between the second inputs of the said coincidence circuitsand the said input leads to apply to the second inputs the said voltagesignals occurring, during operation, on the said input leads andconnections between the outputs of the said coincidence circuits and thestriker electrodes to apply to the said striker electrodes the voltagesignals of the said predetermined value which, during operation, aregated to the outputs of the said coincidence circuits and which renderthe said gas tubes conducting, each said coincidence circuit being thusassociated with a different pair of the said'gas tubes which occupyadjacent positions in the chain and the said coincidence circuits whichhave their outputs connected to adjacent gas tubes in the chain havingtheir second inputs connected to different ones of the said input leads.

10. An electric circuit according to claim 9 in which each saidcoincidence circuit comprises a common point, resistance connectedbetween the first input and the common point, and a rectifier elementwhich is connected between the common point and the output and which isconductive towards the output and a second rectifier element which isconnected between the common point and the second input and which isconductive towards the second input.

11. -An electric circuit according to claim 9 in which the saidcoincidence circuits connect said gas tubes in a continuous chain.

12. An electric circuit according to claim 9 in which individualcapacitance means is provided for each gas tube, each said capacitancemeans being connected in shunt with the individual resistance meansofthe associated gas tube to provide an exponential rise and fall to thevoltages developed across said individual resistance means and in whichthere are provided resistance connected in common to the anodes of thegas tubes and mutual extinguishing means including the commonresi'stance and said capacitance means whereby the conduction of any oneof said gas tubes causes any previously conducting gas tube to beextinguished.

13. An electric circuit according to claim 9 in which said gas tubes arecold cathode gas discharge triodes.

14. An electric circuit comprising a plurality of gas discharge tubeswhich each has an anode, a cathode and a striker electrode, a directcurrent power source for energizing said gas tubes, a small plurality ofinput leads, means to apply voltage signals, each of a predeterminedvalue, to said input leads in a particular sequence so that such avoltage signal occurs on only one input lead at a time, individualresistance means connected between the cathode of each gas tube and thenegative side of said power source to derive a voltage signal of saidpredetermined value from the discharge current through the gas tube,when conducting, individual capacitance means connected between thecathode of each gas tube and the negative side of said power source toprovide an exponential rise and fall to the voltages occurring at thecathode, resistance connected in common to the anodes of said gas tubes,a connection from the positive side of said power source to said common"resistance, the said power source, the common resistance and the saidcapacitance means acting to cause a mutual extinguishing action betweenthe gas tubes whereby the conduction of any one of the said gas tubescauses any previously conducting gas tube to be extinguished, and aplurality of gating circuits which connect said gas tubes in a chain forsequential striking, one at a time, in response to said voltage signalsoccurring on the input leads in the particular sequence, each gatingcircuit coupling a different pair of adjacent gas tubes in the chain andhaving a first input connected to the cathode of the first gas tube ofthe associated pair, a' second input connected to one of the input leadsand an output connected to the striker electrode of the second gas tubeof the associated pair, adjacent gating circuits in the chain havingtheir second inputs connected to difierent ones of the said input leadsand each gating circuit being adapted to gate a striking voltage to thestriker electrode of the second gas tube of the associated pair torender said second gas tube conducting upon the coincidence of voltagesignals of said predetermined value on the first and second inputs ofthe gating circuit.

15. An electric circuit according to .claim 14 in which the said gatingcircuits connect said gas tubes in a continuous chain.

16. An electric circuit according to claim 14 in which each said gatingcircuit comprises a common point, resistance connected between the firstinput and the common point, a first rectifier element which is connectedbetween the common point and the output and which is conductive towardsthe output and a second rectifier element which is connected between thecommon point and the second input and which is conductive towards thesecond input.

17. An electric circuit according to claim 14 in which said gas tubesare cold cathode discharge triodes.

18. An arrangement comprising at least two electric circuits which areeach in accordance with claim 14, there being provided connections fromthe input leads of one of said circuits each to the cathode of adifferent gas tube in the other one of said circuits.

19. An electrical circuit comprising a plurality of gas discharge tubeswhich each has an anode, a cathode and a striker electrode, a positivesupply conductor which is for connection to the positive side of adirect current power source for energizing the gas tubes and to whichsaid anodes are connected, a negative supply conductor for connection tothe negative side of said power source, a plurality of resistance meanswhich are each connected between a different one of said cathodes andthe negative supply conductor, and which of a predetermined value fromthe discharge current that flows through the associated gas tube whenconducting, at least two input leads and a plurality of signal gatingcircuits which connect the gas tubes in a chain for sequential strikingin response to voltage signals of the predetermined value occurring in aparticular sequence between the input leads and the negative supplyconductor, each are each to derive a voltage gating circuit coupling adifferent pairof adjacent gas tubes'in the chain and comprising aresistance-rectifier network which. interconnects the cathode of. thefirst gas tube of the associated pair, the striker electrode of thesecond gas tube of that pair and, one of the input leads so that theflow of electric current is permitted from the associated, cathode toboth the associated striker electrode and input lead, adjacent gatingcircuits in the chain being connected to, different, ones of the inputleads and each gating circuit being arranged to apply a striking,voltage of the predetermined. value between the striker electrode andcathode, of thesecond gas, tube of its associated pair to render thatgas tube conducting only upon the occur.-

rence of the, predetermined voltage between the cathode of the first gastube oi that pair and the negative supply conductor and also between theassociated input lead and the negative supply conductor.

References Cited inthe file, of this patent, UNITED STATES PATENTS2,401,657 Mumma June 4,v 1946 2,426,279 Mumrna Aug. 26', 1,947 2,549,779Crenshaw Apr. 24, 1951 2,646,534 Manley July 21,1953 2,758,250 RidlerAug. 7, 1956

